Recently I updated Jetpack to its latest version 2.1.1. However today I noticed that my stats are not populating, it says ("We were unable to get your stats just now").

Then I tried deactivate and activate the plugin. On activation, It prompted me to connect with wordpress.com. However on clicking connect to WordPress button I receive 404 error for the below url.
/wp-admin/admin.php?page=jetpack&action=register&_wpnonce=e7a79d9929

Since I have a premium theme i tried with basic theme , still not working.